An optician wants to prescribe glasses to an office worker. Since the patient spends much of his time staring at computer screens, he would like his glasses to have an anti-reflective coating that primarily eliminates reflections of blue light (470nm wavelength). If the coating material has an index of refraction ncoat = 1.30 and the glasses lens has an index of refraction nglass= 1.52, what is the thickness of the thinnest possible coating layer that would eliminate blue light reflections?